19997139 has 16 divisors (see below), whose sum is σ = 28974080. Its totient is φ = 12221280.

The previous prime is 19997129. The next prime is 19997147. The reversal of 19997139 is 93179991.

It is not a de Polignac number, because 19997139 - 2⁷ = 19997011 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19997119) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3892 + ... + 7425.

It is an arithmetic number, because the mean of its divisors is an integer number (1810880).

Almost surely, 2^19997139 is an apocalyptic number.

19997139 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

19997139 is a deficient number, since it is larger than the sum of its proper divisors (8976941).

19997139 is a wasteful number, since it uses less digits than its factorization.

19997139 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11370.

The product of its digits is 137781, while the sum is 48.

The square root of 19997139 is about 4471.8160740352. The cubic root of 19997139 is about 271.4288177943.

The spelling of 19997139 in words is "nineteen million, nine hundred ninety-seven thousand, one hundred thirty-nine".